Amazon.com is offering a Buy 2 Get 1 Free promotion, or as they call it, 3 For 2, on a good chunk of video games. This isn't just older titles, but a lot of newer titles as well.
A quick gander at the list reveals a few co-op titles as well like: Operation Flashpoint 2, Madden 10, Guitar Hero 5, Beatles Rock Band, NHL 10, Gears of War 2, Halo 3, Call of Duty: World at War, and Star Wars the Clone Wars: Republic Heroes.
In a season of gaming when wallets are empty due to a plethora of new releases, a deal like this is very welcomed. And remember, all purchases using the above link help support Co-Optimus!